Multichamber smelting furnace



July 10, 1962 J. P. ROHN 3,043,895

MULTICHAMBER SMELTING FURNACE Filed April 2'7, 1959 H44 P&nr BY will bedrawn back into the respective chambers.

Patented July 10, 1962 7 3,043,895 MULTICHAMBER SMELTlNG FURNACE JohannPeter Rohn, Hochkirchen, near Koln, Germany,

assignor to Russ-Elektroofen K.G., Koln-Bayenthal,

Germany, a German firm Filed Apr. 27, 1959, Ser. No. 809,132 Claimspriority, application Germany Apr. 28, 1958 10 Claims. (Cl. 13-27) Thepresent invention relates to a multichamber furnace for melting metals.

In the design and operation of melting furnaces for metals, especiallynonferrous and light metals, but also for iron, many efforts have beenmade to maintain the molten metal at the place of its discharge from thefurnace as pure and as quiet and undisturbed as possible.

For this purpose, there have been prior disclosures of furnace designswhich consisted of two adjacent parallel chambers which were connectedwith each otherat the bottom by channels, and wherein the space betweenthe two chambers was filled out by the electric heating coil whichsurrounded the connecting channels between the chambers and was usedprimarily for melting the metal within these channels.

Although a furnace design of this type has the advantage of having a lowheight and of also achieving a relatively quiet metal bath, it also hasa series of disadvantages which have prevented it from being usedextensively. The foremost deficiency of this furnace design is the factthat the metal is melted in both chambers. Consequently, the material isalso agitated in both chambers, with the result that the metals will notproperly alloy with each other. Furthermore, this furnace design isalways subject to the danger that the channels will become overheatedand to the further danger that, because of the prevailing flowconditions, such overheated metal It has also been found that the largesurface of the metal bath and the large sump of metal which is necessaryfor starting the operation of the furnace constitute a deficiency ofthis furnace design.

In order to overcome the above-mentioned disadvantages and to attain theleast possible movement of the metal bath and the greatest possiblepurity of the calmed molten metal at the point of its removal from thebath, there have been other furnace designs in which one chamber servedsolely as a melting and alloying chamber, while the other chamber wasdesigned for maintaining the metal at the proper temperature and forpermitting its removal for subsequent use. This heat-maintaining andoutput chamber was made smaller than the melting chamber and wasconnected with the latter by a channel 'at the bottom, and the meltingchamber, in turn, was

extended downwardly to form a melting trough which alone was acted uponby the electric heating coil. The metal was charged into the meltingchamber and the actual melting occurred in the downwardly extendingtrough so that the molten metal could become quiet within this troughand the lighter impurities could rise toward the surface. Consequently,only purified and quiet metalcould enter into .the heat-maintaining andoutput chamber. An excessive heating of the channels was thus avoidedand only a relatively small sump was required for starting theoperation.

However, such a furnace also has the disadvantage of a relatively largebath surface and thus of a considerable oxidation of such surface.Furthermore, the metal is heated more intensively in the melting chamberthan in the adjacent heat-maintaining and removal chamber which is notalfected by the heating coil. In both types of furnaces as abovedescribed it was also found to be a very great disadvantage that thelining thereof with a refractory material was extremely diflicult. T-hetamping of such material around the two parallel chambers, theconnecting channels between them, the troughlike downward extension ofthe melting chamber and other furnace parts was a very complicated andexpensive procedure.

it is an object of the present invention to overcome the above-mentioneddisadvantages of the known furnace designs by proceeding along entirelynew directions different from all the attempts which have previouslybeen made to avoid these disadvantages.

A further object of the invention is to provide a furnace which permitsthe molten metal to be removed therefrom in a refined condition withoutany disturbing movement of the bath in the removal chamber.

Another important feature of the new furnace design is the fact thatthere are no connecting channels between the chambers, and that thefurnace is of a very low height. It also permits an easy preparation andthus an easy possibility of alloying, and a preferred embodiment of theinvention also permits thefurnace to be started with a solid charge.

More particularly, the invention therefore relates to an electricmultichamber furnace for smelting various metals including iron andsteel, which comprises a melting chamber and one or moreheat-maintaining and removal chambers. The most distinguishing featureof the new furnace is the fact that the heat-maintaining and removalchamber or chambers are provided in the form of one or more insertswhich are mounted within the melting chamber near the side wall thereof,and that one or more apertures are provided in the bottom or side wallof such insert chamber for the fiow of molten metal into the same afterit has been refined in the melting chamber.

The melting chamber of the furnace may be easily lined with brick or bytamping the refractory material in place. However, such lining is notabsolutely necessary. If the kind of alloy to be produced is to bechanged frequently, a crucible may be removably inserted into thefurnace coil. Such a crucible may consist of refractory material alonewhich has been molded or tamped into shape and then been calcined. Sucha crucible may, however, also consist of graphite or a suitable alloy ofsteel or iron.

Further objects, features, and advantages of the present invention willappear from the following detailed description thereof, particularlywhen read with reference to the accompanying drawings, in which FIGURE 1shows a central vertical section of the furnace according to theinvention on a reduced scale;

FIGURE 2 shows at the upper part a plan view of onehalf of the furnaceaccording to FIGURE 1 without the heating coil and without the outerframe and cover, and at the lower part a horizontal cross section of theother half of the furnace, also without the supporting frame; whileFIGURES 3 and 4 show diagrammatically two modifications of theinvention.

FIGURE 1 of the drawings illustrates a preferred embodiment of theinvention, namely, a crucible furnace which permits the operation of thefurnace to be started with a solid charge. The melting chamber 1 has anupper opening A through which the solid metal is inserted so as to bemelted within chamber -1 by an electric heating chambers side-by-side,for example, a melting chamber and a heat-maintaining and removal oroutput chamber which are connected by channels, but that one chamber,namely, the removal chamber, is disposed within the other meltingchamber. This new furnace design has the advantage that the entirefurnace not only requires considerably less space, but that the dangeris completely avoided that the connecting channels between the twochambers will be excessively heated. Furthermore, the new furnace may bebuilt in the form of a crucible furnace.

The output or removal chamber 8 is made in the form of an insert '9 ofany suitable material which is removably suspended in the meltingchamber 1 and may, for example, be secured to the furnace cover It Inthe embodiment according to FIGURE 1, the insert 9 is made of a conicalshape and inserted into a ring 11, the inner surface 12 of which islikewise conical in accordance with the angle of the conical outersurface of insert 9. The upper end of chamber 8 may be closed by a cover10.

Insert 9 has one or more apertures 14 in its bottom through which themolten metal M may flow from the melting chamber 1 into the removalchamber 8, as indicated in FIGURE 1 by the arrows. If desired, the sidewall of the insert 9 may also be provided with such apertures. Since theinterfering movements of the bath of molten metal in the melting chamber1 occur primarily near the surface thereof and the impurities generallylikewise collect near the surface, the molten metal rising into theremoval chamber 8 through the aperture 14 at a point far below thesurface of the metal in chamber 1 will be entirely free of impurities aswell as entirely quiet, that is, without any agitation. This refinedmetal may then be easily ladled out of the removal chamber 8 after thecover 13- has been removed.

The upper part of FIGURE 2 shows a plan view of onehalf of the furnaceaccording to FIGURE 1 after the cover 13 has been removed, and alsowithout the heating coil 2 and the supporting frame 7, while the lowerpart of FIGURE 2 shows a horizontal cross section of the furnace takenunderneath the crucible insert 9 in FIG- URE 1 and also without thesupporting frame 7. Both FIGURES 1 and 2 show the eccentric arrangementof the insert 9 in which the molten metal is maintained at the propertemperature by the surrounding body of metal in the melting chamber 1.This eccentric position of insert 9 relative to melting chamber 1 hasthe advantage that the insert is more easily accessible from one side ofthe furnace and that sufficient space will be left for easily chargingthe furnace through the top opening A. Naturally, if for any reason itshould be desired, the insert 9 may also be mounted centrally of chamber1.

In the modification of the invention as illustrated in FIGURE 3 thefurnace chamber 15 is not made round but oval so that, when the insert16 is mounted eccentrically therein, the area B for charging the furnacewill be even larger than the corresponding area of the round furnaceaccording to FIGURES 1 and 2.

It is also possible according to the invention to provide two or moreremoval chambers within one melting chamber. One preferred embodimentwith two removal chambers in an oval furnace 17 is illustrated in FIGURE4. These two chambers are again provided in the form of inserts 18 and18a which are disposed near the opposite highly curved wall portions ofthe oval melting chamber 17 and are shaped so that the sides 19- thereoffacing towardthe center of chamber 17 are flattened, while the otherparts of the inserts substantially correspond to the curvature ofchamber 17. Through this flattened shape of the inserts a large spaceCwill be left free between them through which the furnace may be easilycharged.

The furnace insert forming the removal chamber may be made of anysuitable material, for example, graphite, fireproof clay, calcinedmagnesite, silimanite, or a special metal alloy. If during the operationof the furnace, the insert should be broken or damaged, it may be easilyremoved and replaced by a new insert without requiring any longinterruption of the operation since the broken parts will not alfect themolten metal, but will pass to the surface of the molten metal in themelting chamber from which they may then be removed.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments, but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed my invention, what I claim is:

1. An electric melting furnace for smelting metals comprising, incombination, a single, upright, stationary melting chamber made fromelectrically non-conductive material and having an upper charge openingfor charging the melting chamber with metal to be molten therein; atleast one electric coil surrounding said melting chamber; and at leastone insert chamber arranged within said melting chamber eccentricallywith respect thereto and with respect to said coil surrounding saidmelting chamber and extending from the top of said melting chambertoward the bottom thereof so as to be adapted to dip deeply below thesurface of the molten metal in said melting chamber, said insert chamberhaving a bottom portion formed with at least one aperture therethroughfrom which the refined and molten metal may enter from said meltingchamber into said insert chamber to be maintained in the latter in quietstate and proper temperature and for being removed therefrom, the innervolume of said insert chamber being considerably smaller than the innervolume of said melting chamber.

2. A furnace as defined in claim 1 in which said aperture is arrangedsubstantially centrally through the bottom wall of said insert chamber.

3. A furnace as defined in claim 1, wherein said melting chamber has asubstantially circular cross section and said insert chamber is disposedeccentrically within said melting chamber near one side thereof.

4. A furnace as defined in claim 1, wherein said melting chamber has anoblong cross section and said insert chamber is disposed within saidmelting chamber near one end thereof.

5. A furnace as defined in claim 1, wherein at least two of said insertchambers are disposed within said melting chamber in a spaced relationto each other to accommodate said charge opening.

6. A furnace as defined in claim 1, wherein said insert chamber has aflattened side in the direction facing toward said charge opening.

7. A furnace as defined in claim 1, further comprising a cover on saidmelting chamber having a conical opening therein, said insert chamberhaving a conical shape adapted to be suspended within said conicalopening in said cover.

8. A furnace as defined in claim 1, further comprising a lining ofrefractory material on the inner wall of said melting chamber.

9. A furnace as defined in claim 8, wherein said lining forms anintegral unit adapted to be inserted into and removed from said innerwall.

10. A furnace as defined in claim 1, wherein said melting chambercomprises a removable unit of refractory material.

References Cited in the file of this patent UNITED STATES PATENTS 5UNITED STATES PATENTS Wilke Nov. 4, 1924 Goldberg May 11., 1937 McParlinJan. 2, 1949 5 Cornell June 7, 1949 6 Lillienberg Aug. 11, 1953 Hogel eta1. Aug. 25, 1953 Rusler June 30, 1959 FOREIGN PATENTS Great BritainJune 4, 1948

